Manufacture of polished sheet metal.



l Patented lune 25,` |90I. Y A. J. DEMMLER. IIANUFACTURE 0F POLISHEDSHEET METAL.

(Application med Aug. 4, 1900.)

No Model.)

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Q q @a UN rTEn STATES PATENT OEEicE.

ALBERT J. DEMMLER, OF VELLSVILLE, OHIO.

MANUFACTURE OF POLISHED SHEET METAL.

SPECIFICATION .forming part of Letters Patent No. 677,022, dated June25, 1901.

Application filed August 4, 1900. Serial No. 25,856. (No specimens.)

To all whom it 71mg/ concern:

Be it known that I, ALBERT J. DEMMLEE, a resident of Vellsville, in thecounty of Oolumbiana and State of Ohio, have invented a new and usefulImprovement in the Manufacture of Polished Sheet Metal; and I do herebydeclare the following to be a full, clear, and exact descriptionthereof.

My invention relates to the manufacture of polished sheet metal, andmore particularly to the manufacture of polished sheet iron or steel,within which term I of course include thin plate metal, its object beingto provide a rapid and efcient method of making the same, so as toincrease the output and obtain a greater proportion of good or moreevenly iinished sheets.

The process generally practiced in the manufacture of what is known asblued or polished sheet iron or steel is set forth in Letters Patent No.608,432, granted to iVilliarn M. Theobald August 2, 1898, and has beento raise the same to a heat practically the saine as the ordinaryannealing temperature without contact with the atmosphere and at acertain temperature expose the sheets to the atmosphere, each sheetbeing exposed by turning it over from the pile of sheets as heated ontoa truck until the truck contained about one hundred sheets, when it wastaken to the polishingrolls, between which the sheets `were passed oneor two ata time. This process, while being the best developed forforming blued or polished sheet-iron, was slow and in addition to thathad the objection that in turning over the sheets to expose them itwasdifficult to bring the edges of the sheets into exact line, so that theextreme edges of the sheets where they extended beyond those in contacttherewith were liable to be oxidized to greater extent than the bodiesof the sheets, while in so turning over the sheets it Was practicallyimpossible to make them lie so close to each other that the air wouldnot penetrate into the pile,and parts of the sheets would therefore beoveroxidized. Another difficulty found was that the sheets first placedupon the truck in exposing them for oxidizing were the last fed to therolls and were liable to be too cool for proper polishing and fasteningthe oXid to the bodies of the sheets. By the present invention thesedifficulties are overcome and more uniformly finished sheets areproduced, While the output is increased tWenty-ivetQ) to fifty (50) percent.

and the percentage of good sheets also largely increased.

In the practice of the invention I heat the sheet metal in bulk andcarry the sheet metal in bulk as heated from the annealing or othersuitable furnace to the rolls, for this purpose preferably interposingin the charge of sheets in the annealing box or furnace a number ofsupporting-slabs by which the piles can be handled in bulk, and I feedthe sheets from such pile directly to the finishing-rolls, theparticular advantages of the invention,as well as the other stepsthereof, being hereinafter more particularly set forth. I

To enable others skilled in the art to practice my invention, I willdescribe the same more fully, referring to the accompanying drawings, inwhich- Figure lis a side View, partly broken away, of an annealing-box,showing the sheets supported in bulk therein, the overhead grapplearranged to carry the same to the rolls, and the i rolls themselves,with the sheets, supported in front thereof. Fig. 2 is a cross-sectionof a heating-furnace containing the annealingbox and illustrating tliemanner in which the sheets are built up therein. Fig. 3 is across-section of another form of annealingbox. Fig. et is across-section of a mufliefurnace suitable for heating the sheet metal inbulk, and Fig. 5 is an end view of the hotbed of Fig. l with thesupporting-slab resting thereon.

In the practice of my invention I may employ any suitable furnace forheating the sheets and preparing them for the other steps of the method,either inclosing them in a .suitable box, generally termed anannealing-box, or heating them Within a muffle-furnace, such as shown inFig. 4. I prefer to heat the sheets in anuealingboxes and haveillustrated for that purpose two different kinds of boxes. The ordinaryannealing-box (shown in Fig. 2) has the bottom 2 supported on balls 3and the coveriresting on the bottom and inclosing the sheets to beheated. This box is inserted in a suitable furnace, which is illustrateddiagrammatically in the drawings at 5, the gases entering through theflues (5 at each side of the annealing-box. For ease in handling thesheets in bulk as heated I support them upon slabs, using for thatpurpose the bottom slab 7, which has at ICO its outery edges theupwardly-turning anges 8, with the lifting-lips 9,while within the bodyof sheets are interposed the lifting-slabs 10 ll l2. I prefer to formthese slabs of caststeel, the slabs being made of sufficient thicknessto insure support of the body of plates thereon even when the slabs arehighly heated. In Fig. 3 I have illustrated another form ofannealing-box composed of a series of sections 13, 14, and 15, supportedone above the other in such way that the sheets in any section of thestack can be separately exposed, while the bottom 16 of each sectionacts as a supporting-slab for carrying the pile of sheets to the rolls.In either case where a single box or sectional box is employed toprevent entrance of air to the sheets the joints of the boxes aresuitably luted with sand, as at 17. The particular improvements,including the interposed slabs in the ordinary box and the sectionalboxes, are set forth in companion applications of even date, Serial Nos.25,853 and 25,854, and therefore will not require any furtherdescription.

In Fig. 4I have illustrated the ordinary muffle-furnaee for the heatingof the sheet metal in bulk, this furnace having the side walls 18, roof19, and fines 2O and having supported therein the muffie-chamber 2l, inwhich the metal is inserted in bulk, such as when resting upon the slabs22, and by which it can be inserted within and withdrawn from themunie-chamber by any suitable means, it of course being understood thatduring the heat- `ing of the sheet metal the munie-chamber is to beclosed and luted to prevent overcontact with the atmosphere.

In order to handle the different piles of sheets, I mayemploy anysuitable derrick or transferring apparatus, that particularlyillustrated in the drawings being suitable for the handling of thesheets when in the annealing-boxes and having grapples 23, provided Withtoes 24, which pass under the supporting-slabs and lift the same, thesegrapples running on an overhead track 25 and being adapted to carry thepiles of sheets in bulk as heated from the annealing-boxes to the rolls,and for the purpose of lifting the covers from the annealing-boxes thegrapples may carry links 26. The rolls employed are usually the two-highfinishingrolls, such as used in the ordinary sheet-mill, the rolls beingshown at 27 and 28, while in front of the same are the supports 29, onwhich the slabs supporting the pile of sheets `rest, while ou theopposite side of the rolls I of course employ any suitable supports 30to receive the sheets as they are delivered therefrom. I also prefer toemploy in connection with the rolls an air-blast playing upon the centerof the rolls during the rolling of the sheet metal, as described inLetters Patent No. 626,847, granted to IVilliam M. Theobald June 13,1899, as shown at 3l, the air being control-led by a suitable valve 32,so that the current of air can be regulated to maintain the rolls ofeven diameter and to aid inthe oxidizing of the under faces of thesheets. The slabs on which the sheets are carried in bulk to the rollsare of course raised to a high heat within the annealing box or furnace,and they act as hot beds to maintain the heat of the sheets in the lowerpart of the pile during the rolling operation, as described in acompanion application, Serial No. 25,853. Any suitable kind of hot bedmay be employed for this purpose.

In employing the invention in the manufacture of what is known as bluedior polished sheet iron or steel I generally proceed as follows: Thesheets or thin plates as they are received from the rolling-mill, andpreferably Without any previous cleaning by acid or like means, (thoughof course such cleaning may be employed, if desired,) are first piled inany suitable way to be inserted within the furnace, being either piledin the annealingbox, as illustrated in Figs. 1, 2, and 3, or piled uponslabs which are inserted in the mufflefurnace, as shown in Fig. at. Asthe sheets are piled when cold, it is preferred to bring the edges ofthe different piles even, so as to prevent overexposure of the edges ofthe sheets, and as the sheets remain in such position until they are fedto the rolls the difficulty of the overexposure of the edges of some ofthe sheets is overcome. The thickness or height of the pile of sheetswill depend upon the thickness of the sheetsand the rapidity with whichthey can be fed to the rolls, the piles generally varying in height fromsix to fifteen inches and containing from one hundred to five hundredsheets. After the sheets are inserted in the furnace, either within theannealing box or mufiie, the furnace is gradually raised to a sufficientheat to heatthe mass of sheets throughout to a point several hundreddegrees higher than that at whichit is desired vto roll the samethat is,the heat is maintained until the mass of sheets in the furnace is soakedthroughout, and thereby brought to a sufficient heat to permit theinevitable cooling during the handling and yet not lower the temperatureof the sheets below what is termed a warm heat when passing through therolls. lVhen raised to the proper temperature, which on account of theslow heating considered proper requires from six to twelve hours, thefurnace may either be permitted to cool down or the boxes containing thesheets removed therefrom, it being preferred that the sheets shall notbe exposed to the atmosphere at a higher temperature than a scarcelyvisible red heat, which might be roughly stated at about 1,000Fahrenheit, more or less. Vhere the sheets have been heated in theordinary box, as soon as they are uncovered, by means of the grappleengaging with one of the interposed slabs, a pile is carried from thebox to the rolls in bulk as it has been heated, it being preferred tohave a number of sets of rolls, so that the several piles can beimmediately carried to IOO IIO

the rolls for finishing, though if that is not practicable the cover ofthe annealing-box can be replaced. Where the sectional annealing-boxesare used, one section can be withdrawn at a time and carried to anduncovered in front of the rolls, and where the sheets are supported onthe slabs in the multle-furnace separate slabs, each supporting a pile,can be removed and carried to the rolls. The sheets are then withdrawnfrom the piles in front of the rolls and passed between the rolls at atemperature suitable for both oxidation and for the fastening of theoXid to the sheets. This temperature should not be under about 300D. Asthe edges of the piles are made even before heating and during theheating of the piles, the weight thereof forces the sheets into closercontact, the difficulty of overexposure of the bodies or of the edges isovercome, and the proper oxidation or bluing in the bodies and close tothe edges is obtained. As one sheet is withdrawn from the pile its undersurface is for the first time exposed to the atmosphere; but it is foundthat in so working a sufficient exposure is obtained to produce thedesired color or iinish, the air-blast from the pipe 3l for maintainingthe rolls of even diameter apparently aiding in giving the proper colorand finish to the lower face of the sheet. Before the withdrawal of suchsheet from the pile the top face of the next sheet is exposed foroxidizing, and the sheets are so fed to the rolls until the pile ofsheets supported on the slab has all been rolled. The sheets may berolled two at a time, if desired, where polish is only desired on oneface of the sheet. During such rolling` operation on account of the heatof the hot-bed or slab on which the bulk of sheets rests it is evidentthat the heat of the sheets in the lower part of the pile is maintainedon account of the heat stored in the hot bed, it being found that in soworking the lower sheets obtain practically as perfect a bluing andfinishing as those in the upper part of the pile and are maintained at asufficiently high heat for such purpose.

Practical use of the invention shows that almost all the sheets in thepile are finished of first quality, the proportion of Iirst qualitysheets obtained being generally over ninety per cent., the sheetsproduced being of fairly even color throughout, though of course onesheet may vary from another sheet in shade, The labor in manufacture isalso materially reduced, as the only-handling of the sheets afterheating is the carrying of the same by the transfer device to the rollsand the feeding of the sheets from such pile into the rolls. In additionto this, as two or more sets of rolls may be employed and a pile ofsheets carried to each set of rolls, the sheets heated at one time inany suitable box or furnace can be rolled and iinished much closer tothe best heat for finishing, while the output of the plant may be verymaterially increased.

Vhile I have described the invention as especially applicable to themanufacture of blued or polished sheet iron or steel, it isevident thatit has advantages in the manufacture of different classes of sheetmetal, including sheet copper, brass, dac., and I desire to include thesame within my invention.

What I claim as my invention, and desire to secure by Letters Patent,is-

1. The method of making sheet metal, consisting in heating a pile ofsheets in bulk, carrying the sheets in bulk as heated to the rolls andlifting the heated sheets from the pile and passing them between therolls.

2. The method of making sheet metal, consisting in heating a pile ofsheets, carrying the sheets in bulk as heated to the rolls, supportingthem in bulk on a hot bed in position for feeding to the rolls andlifting the sheets from the pile and passing them between the rolls.

3. The method of making blued or polished sheet iron or steel,consisting in heating a pile of sheets when protected from theatmosphere, carrying the sheets in bulk as heated to the rolls and whilesaid sheets are still heated, lifting them from the pile and passingthem sheet by sheet between the rolls.

4. The method of making blued or polished sheet iron or steel,consisting in heating a pile of sheets when protected from theatmosphere, carrying the sheets in bulk as heated to the rolls and Whilesaid sheets are still heated, lifting them from the pile and pass- IOOing them sheet by sheet between the rolls and projecting air upon theunder faces of the sheets when passing to the rolls.

5. The method of making blued or polished sheet iron or steel,consisting in heating a pile of sheets when protected from theatmosphere, carrying the sheets in bulk as heated to the rolls andsupporting them in bulk on a hot bed and lifting the sheets from thepile and passing them between rolls.

6. The method of making blued or polished sheet iron or steel,consisting in inclosing a pile of sheets within an annealing-box,heating them in bulk when inclosed therein, carrying the sheets in bulkas heated to the rolls and lifting them from the pile and passing themsheet by sheet between the rolls.

7. The method of making blued or polished sheet iron or steel,consisting in inclosing a pile of sheets within an annealing-box,heating them in bulk and carrying the sheets in bulk as heated and wheninclosed in such box to the rolls, opening the box, and lifting thesheets from the pile and passing them between the rolls.

In testimony whereof I, the said ALBERT J. DEMMLER, have hereunto set myhand.

ALBERT J. DEMMLER.

Witnesses:

JAMEs I. KAY, J. D. BUCKLES?.

IIO

